The main objective of this project is to evaluate the role of menthol cigarette use in explaining racial and ethnic differences in exposure to tobacco smoke components, among smokers in the United States (U.S.). Although Black smokers consume fewer cigarettes per day compared to White smokers, they have higher serum cotinine concentrations, are less likely to successfully quit smoking, and are at greater risk for some tobacco-related diseases. Several explanations have been proposed for these racial disparities, including differences in the prevalence of menthol cigarette use. Menthol has anesthetizing properties that could increase inhalation depth and tobacco intake per cigarette and it has been shown to impact nicotine metabolism, which may affect cotinine levels and nicotine dependency. In the proposed study, we will analyze the extensive smoking questionnaire and biomarker data from the National Health and Nutrition Examination Survey (NHANES), a series of nationally representative surveys of the U.S. population. We will combine five successive waves of data from the NHANES, conducted between 1999 and 2008. Serum cotinine, blood cadmium, and urine polycyclic aromatic hydrocarbons (PAHs) are established biomarkers of tobacco use that are available in the NHANES database and will be used in the analysis. Serum cotinine is a specific biomarker of exposure to nicotine, the addictive component of tobacco. Cadmium and PAHs are highly toxic and carcinogenic tobacco components. While cotinine and PAHs reflect relatively recent exposure, cadmium can be used to characterize longer-term tobacco use. Using NHANES, we will describe the association of race/ethnicity and menthol cigarette use with biomarker concentrations using geometric mean ratios (and 95% CI) derived from regression models of log-transformed concentrations. In addition to crude analyses, models will be progressively adjusted for cigarettes smoked per day, sociodemographic characteristics, other smoking-related characteristics, and biomarker-specific determinants. Analyses will be conducted to account for the complex survey design structure and all estimates will be weighted to the U.S. population. This proposed research will utilize existing, publicly accessible data to examine racial/ethnic disparities in tobacco use biomarkers and the contribution of menthol cigarette use to these disparities. Examining differences in biomarkers of tobacco-related compounds will provide insight on the potential for menthol additives to contribute to nicotine addiction and long-term disease risk.